Module 3 Flashcards
Central Processing Unit (CPU)?
The device that “runs” software programs.
Software is composed of many simple instructions.
The CPU processes these instructions and directs other components to perform actions, such as displaying an image on the screen or printing a document.
What is Random Access Memory
(RAM)?
When a program is started, its instructions are loaded into system memory.
System memory uses a type of technology called Random Access Memory (RAM).
Having more RAM allows the PC to open more programs simultaneously and work on large files more efficiently.
As well as system memory size, the speed of the memory subsystem is also important.
The CPU fetches instructions from system memory as it needs them.
This means that the bus between the CPU and memory, often referred to as the Front Side
Bus (FSB), must be as fast as possible.
What are the types of fixed disks, and why are they important?
Because RAM only works while the power is on, when the computer is turned off, programs and data are stored on a Hard Disk Drive (HDD) or Solid State
Drive (SSD).
The type and specification of the mass storage drive such as an HDD or SSD is important for three reasons:
■ If there is not enough space, fewer programs and data files can be stored on the computer.
■ If the disk is not fast enough, performance will suffer when the computer tries to load programs and data files into memory (read operations) or write data from memory to files.
■ The computer may use part of the hard disk to supplement system RAM (virtual memory).
If the computer does not have much system RAM, it
helps for the hard disk to be fast otherwise accessing virtual memory often will reduce performance even more than usual.
HDDs are based on a magnetic disk technology.
SSDs use a type of transistor-based memory called flash memory and are much faster than HDDs.
What is a Graphics Processing Unit (GPU)?
Displaying a high-resolution image to the user requires a lot of processing power, especially if the image changes rapidly, as with video, or uses complicated 3D and texture effects, as with computer games.
Consequently, display functions are often performed by a dedicated processor, referred to as the Graphics Processing Unit (GPU).
This might actually be part of the CPU package or a more powerful GPU might be provided on a plug-in expansion card.
What is a network interface and what are the two main ways of making a network link?
Computers, smartphones, and tablets are almost always used as part of a computer network.
They can use the network to share information locally and to access data over the Internet.
There are two main ways of making a network link:
■ Wired network—on a home network, the computer will be connected to an Internet router via an Ethernet port.
On a business network, the computer will be connected to the wider network via an Ethernet switch. The Ethernet port in the computer is provided by a Network Interface Card (NIC).
Almost all workstation computers come with a NIC on the motherboard (onboard card).
Servers may have additional NICs supplied on expansion (or add-on) cards.
The connection to the router is made using a cable with
RJ-45 connectors on each end.
■ Wireless network—most home networks support Wi-Fi radio networking so that computing devices do not have to be cabled to the Internet router to access the network.
Most laptops, smartphones, and tablets have built in
Wi-Fi adapters.
Workstation computers more typically have a Wi-Fi add-on card.
Most business networks support Wi-Fi via wireless access points.
What is a motherboard?
If you open up a PC or a laptop, the main thing you will see is the motherboard (or system board).
The motherboard is a Printed Circuit Board (PCB) with some built-in processors (the chipset), sockets and slots for upgradable components (CPU, RAM, adapter cards, disk drives), and wires (buses) to connect them together.
The motherboard determines the upgrade potential of the computer.
If a component is not compatible with the motherboard, it cannot be installed.
A component may not be compatible with the motherboard either because it does not physically fit in the type of sockets available or because it is too new for the motherboard’s chipset to be able to communicate with it.
The motherboard chipset provides “built-in” functions that might otherwise require an adapter card.
Most motherboard chipsets support graphics, audio,
and network adapter functions.
An add-on card may still be used to upgrade those functions though.
What is a processor?
A microprocessor (usually shortened to “processor”) is a programmable integrated circuit—a silicon chip embedded on a ceramic plate.
A silicon chip is a wafer of purified silicon doped with a metal oxide, typically copper or aluminum.
The doping process creates millions of transistors and signal pathways within an area called the die, which provide the electrical on/off states that are the basis of binary computer systems.
PCs contain a number of processors, but the most important is the Central Processing Unit (CPU).
The CPU is commonly described as the “brains” of a
computer; in fact, it is better thought of as a very efficient sorting office.
The CPU cannot think, but it can process simple instructions very, very quickly and
efficiently.
A computer is only as “clever” as its software.
What are some Intel CPU brands?
■ Core—this is Intel’s flagship desktop and mobile CPU series.
The earliest models (Core Solo and Core Duo) were laptop-only chips.
The Core 2 series introduced desktop versions plus 64-bit and multi-core support.
The current product line is divided into Core i3, i5, and i7 brands, with i7 representing the best performing models.
The Core iX brand has been based on successive generations of microarchitectures, named Nehalem,
Sandy Bridge, Ivy Bridge, Haswell, Broadwell, and Skylake.
■ Pentium—the Pentium used to be Intel’s premium 32-bit CPU brand and you may still find Pentium 4-based computers in use.
The Pentium brand has been reintroduced to represent “mid-range” CPU models based on the Core microarchitectures.
■ Celeron—this has long been Intel’s budget brand.
■ Atom—this is a brand designating chips designed for low-power portable devices (smartphones and tablets).
■ Xeon—this brand is aimed at the server/workstation market.
Current Xeons are often differentiated from their Core i counterparts by supporting n-way multiprocessing and ECC memory and coming with larger caches.
What are some AMD CPU brands?
Older AMD brands such as Athlon, Phenom, Sempron, and Turion have been phased out over the last few years.
The following brands represent the company’s Zen microarchitecture in different segments:
■ Ryzen/Threadripper and Ryzen Mobile—this brand now represents AMD’s pitch for the high-end enthusiast segment, replacing older AMD FX chips.
■ Epyc—AMD’s server-class CPU brand, replacing its long-standing Opteron series of chips.
What are ARM CPUs?
CPUs and their chipsets for mobile phones smartphones and tablets are often based on the ARM (Advanced RISC Machine) microarchitecture, such as the Apple A, Samsung Exynos, and nVIDIA Tegra derivatives.
RISC stands for Reduced Instruction Set Computing. RISC microarchitectures use simple instructions processed very quickly.
This contrasts with Complex (CISC) microarchitectures, which use more powerful instructions but process each one more slowly.
Intel’s microarchitecture is CISC with RISC enhancements (micro-ops).
What are the main features of processors?
The CPU is designed to run software programs.
When a software program runs (whether it be an operating system, anti-virus utility, or word processing
application), it is assembled into machine code instructions utilizing the fundamental instruction set of the CPU and loaded into system memory.
The CPU then performs the following operations on these instructions:
■ The Control Unit fetches the next instruction in sequence from system memory to the pipeline.
■ The control unit decodes each instruction in turn and either executes it itself or passes it to the Arithmetic Logic Unit (ALU) or Floating Point Unit (FPU) for execution.
■ The result of the executed instruction is written back to a register or to system memory.
A register is a temporary storage area available to the
different units within the CPU.
This overview is grossly simplified of course.
Over the years, many different internal architectures have been developed to optimize the process of fetch,
decode, execute, and writeback, while retaining compatibility with the basic x86 instruction set, which defines a CPU as IBM PC compatible.
What are the differences in instruction set between 32-bit and 64-bit processors?
The original version of x86 created in 1978 was designed for 16-bit CPUs.
This means that each instruction is 16-bits “wide.”
The first 32-bit CPU was introduced in 1985 and the x86 instruction set was updated to a 32-bit version, called x86-32 or IA-32 (Intel Architecture).
AMD developed the AMD64/x86-64/x64 instruction set now used by most 64-bit CPUs in 2003.
Intel refers to it as EM64T or Intel 64.
The main advantage of 64-bit is the ability to use more system memory.
32-bit systems are limited to addressing up to 4 GB whereas systems with 64-bit CPUs can address 256 Terabytes (or more).
A 64-bit CPU can run a 64-bit or 32-bit OS.
A 32-bit CPU cannot run 64-bit software.
Most workstations and laptops now use 64-bit CPUs. Some budget models might come with a 32-bit chip, though this is increasingly unusual.
Almost all server computers would use a 64-bit CPU with only very old servers relying on 32-bit.
64-bit also dominates the premium smartphone and tablet sector, though 32-bit is still prevalent on budget and midrange models.
What is clock and bus speed?
A CPU’s clock speed is the number of instructions it can process in one second.
As a measure of frequency, this value is expressed in Hertz (Hz).
Early processors had clock speeds measured in Megahertz (MHz), or 1,000,000 times faster than 1 Hz. Modern CPUs run at 1 Gigahertz (GHz) or better.
1 GHz is 1000 times faster than 1 MHz.
When Intel or AMD release a new CPU, they produce a range of models clocked at different maximum speeds (2 GHz, 2.4 GHz, 2.8 GHz, and 3 GHz for instance).
The speed at which the CPU runs is generally seen as a key indicator of performance.
This is certainly true when comparing CPUs with the same architecture but is not necessarily the case otherwise.
Dual-core CPUs (see below) run slower (up to about 3 GHz) than many earlier single core CPUs (up to about 4 GHz), but deliver better performance.
The core clock speed is the speed at which the CPU runs internal processes and accesses cache (see below).
The Front Side Bus speed is the interface between the CPU and system memory.
The speed of the bus is usually determined by the memory controller, which might be part of the motherboard chipset or part of the CPU.
While older bus speeds are typically measured in MHz, modern bus types and memory interfaces work at GHz speeds.
Also, modern memory designs increase bandwidth by transferring data twice per clock cycle (Double Data Rate) and often by transferring data from two memory modules simultaneously (Dual-channel).
What is multiprocessing and dual-core?
Trying to make the CPU work faster by increasing the clock speed has the drawbacks of using a lot of power and generating a lot of heat.
A different approach to making a computer system faster is to use two or more physical CPUs, referred to as Symmetric Multiprocessing (SMP).
An SMP-aware OS can then make efficient use of the processing resources available to run application processes on whichever CPU is available.
SMP means physically installing two or more CPUs in a multi-socket motherboard.
Obviously, this adds significantly to the cost and so is only implemented on servers and high-end workstations.
However, improvements in CPU manufacturing techniques have led to another solution: dual-core CPUs, or Chip Level Multiprocessing (CMP).
A dual-core CPU is essentially two processors combined on the same die.
The market has quickly moved beyond dual-core CPUs to multi-core packages with four or eight processors.
What are system and expansion bus technologies?
A bus is circuitry that connects the various microprocessors and other components on the motherboard.
If you look closely at a motherboard, you will see many tiny wires.
These wires are the circuitry that makes up a bus
imprinted on the Printed Circuit Board (PCB) that is the basis of a motherboard (there are actually multiple layers of circuitry in addition to what you can see on the surface). A bus carries four things:
■ Data—the information being transferred between components.
■ Address information—where the data is located in memory.
■ Timing signal—as different components can work at different speeds, the system clock synchronizes the way they communicate over the bus.
■ Power—electricity to run the component.
A PC system has two main types of bus: the system (or local) bus and the expansion bus.
■ The system bus, also referred to as the Front Side Bus (FSB) or local bus, provides connections between the CPU and system memory.
■ The expansion bus, also called the Input/Output (I/O) bus, provides connections between the CPU and add-on components, which can be integrated onto the motherboard, installed as expansion cards, or connected as peripheral devices.
The architecture of the expansion bus depends on what generation the motherboard and CPU platform are.
Broadly speaking, since 1993, PC architecture has been based on one of Peripheral Component Interconnect
(PCI), PCI with AGP (Accelerated Graphics Port), or PCI Express (PCIe).
What are the main components of Peripheral Component Interconnect
(PCI) technologies?
PCI (32-bit) 133 MBps Very old but still used on some
desktops for compatibility; bandwidth is shared between all devices attached to the bus.
AGP 2133 MBps Used for old graphics adapters only.
PCI Express (PCIe) 1.0 250 MBps per lane.
Can use x1, x2, x8, or x16 lanes depending on the size of the slot; uses point-to-point links so each device gets
the full bandwidth of the number of lanes it supports.
PCIe x16 4 GBps Graphics adapters typically use x16
lanes.
PCIe 2.0 500 MBps per
lane
Version 2 doubles the bandwidth per
lane.
PCIe 2.0
x16
8 GBps
PCIe 3.0 1 GBps per
lane
Version 3 doubles the bandwidth per
lane again.
A new computer would most likely have a PCIe x16 slot for a graphics adapter, one or two PCIe x1 slots, and one or two PCI slots for backward compatibility.
What are heatsinks, heat spreaders and thermal paste?
A heatsink is a block of metal with fins.
As the fins expose a larger surface area to the air around the component, a greater cooling effect by convection is achieved.
The heatsink is “glued” to the surface of the chip using thermal paste, also referred to as thermal grease or compound, to ensure the best transfer of heat.
A heatsink is a passive cooling device.
Passive cooling means that it does not require extra energy (electricity) to work.
In order to work well, a heatsink requires good airflow around the PC.
It is important to try to keep “cable clutter” to a minimum and to keep the PC interior free from dust.
As heatsinks are bulky objects with a lot of height, they cannot be used in laptops or other mobiles.
Computers with thin cases use a heat spreader instead.
This is a flat tube with liquid inside.
As the component heats up the liquid, it moves to another part of the tube and is cooled down by a fan or other type of convection.
The cooler liquid then passes back over the component, heats up again, and moves away, creating a constant cooling cycle.
What are fans?
Many PCs have components that generate more heat than can be removed by passive cooling.
A fan improves air flow and so helps to dissipate heat. Fans are used for the power supply and chassis exhaust points.
The fan system will be designed to draw cool air from vents in the front of the case over the motherboard and expel warmed air from the back of the case.
Typically, the speed of the fan is varied according to the
temperature and sensors are used to detect whether a fan has failed.
Smaller fans may be used to improve the performance of the heatsink on the CPU, GPUs, and even hard disks.
A fan is an active cooling device.
It requires power to run. Power is supplied to a CPU or case fan by connecting its power connector to an appropriate header on the motherboard.
What are liquid-based cooling systems?
PCs used for high-end gaming, those with twin graphics cards for instance, and with overclocked components may generate more heat than basic thermal management can cope with.
PCs used where the ambient temperature is very high may also require exceptional cooling measures.
Liquid-based cooling refers to a system of pumping water around the chassis.
Water is a more effective coolant than air convection and a good pump can run more quietly than numerous fans.
On the downside, liquid cooling makes maintenance and upgrades more difficult, requires comparatively more power to run, and is costly.
Liquid cooling is an active cooling technology as the pump requires power to run.
What is BIOS and UEFI System Firmware?
When a computer is powered on, it needs some standard means for the CPU to start processing instructions and initialize the other components.
This is referred to as bootstrapping or more simply as booting.
The bootstrapping process occurs before the operating system software is loaded and is enabled by a low-level operating system called firmware.
The BIOS (Basic Input/Output System) is one example of PC firmware.
It provides industry standard program code to get the essential components of the PC running and ensures that the design of each manufacturer’s motherboard is PC compatible.
Newer motherboards may use a different kind of firmware called UEFI (Unified Extensible Firmware Interface). UEFI provides support for 64-bit CPU operation at boot, a full GUI and mouse operation at boot, and better boot security. A computer with UEFI may also support booting in a legacy BIOS mode.
What is USB?
The Universal Serial Bus (USB) has become the standard means of connecting peripheral devices to a computer.
USB devices are Plug-and-Play.
This means that when a device is connected via the port, Windows can identify the device and try to install a driver for it (make the device usable) automatically. Another feature of USB is that devices are hot-swappable.
This means that Windows can detect and configure a device without requiring a restart.
As well as providing a data connection, USB can supply enough power (about 4.5W) over the cable to run small devices.
Devices that require more power than this, such as optical drives or printers, must be connected to an external power supply.
What are USB Ports and Connectors?
There are several types of USB connector:
■ Type A—for connection to the host. The connector and port are shaped like flat rectangles.
■ Type B—for connection to a device. The connector and port are square, with a beveled top.
There are also small form factor versions of the type B
connector and port:
● Type B Mini—a smaller connector for connection to a device.
This type of connector was seen on early digital cameras but is no longer widely used.
● Type B Micro—an updated connector for smaller devices, such as smartphones and tablets.
The micro connector is distinctively flatter
than the older mini type connector.
■ Type C—a new reversible connector type (can be inserted either way up).
Type A and B USB connectors are always inserted with the USB symbol ( ) facing up.
Type C (USB-C) connectors are reversible (can be inserted either way up).
There are various converter cables with different connector types on each end (for example, a USB Type A to USB-C cable).
What are USB Data Rates?
The data rate for USB 1.1 is 12 Mbps (megabits per second) while the USB 2.0 (Hi-Speed) standard has a nominal data rate of 480 Mbps.
USB 2.0 uses the same connectors as USB 1.1 but a USB 1.1 device plugged into a USB 2.0 port will operate at the lower speed.
The USB 3.0 standard introduces a SuperSpeed mode. SuperSpeed improves the bus bandwidth tenfold (to 5 Gbps or 5000 Mbps) and makes the link full duplex, so a device can send and receive at up to 5 Gbps simultaneously.
USB 3.x receptacles and connectors often have a blue connector tab or housing to distinguish them.
USB 3.1 defines a SuperSpeed+ mode with a data rate of 10 Gbps.
What is Firewire?
The Firewire bus was based on the IEEE 1394 standard and the Small Computer System Interface (SCSI) communications protocol.
Firewire was a competitor to USB but never received mainstream support amongst PC vendors.
It was used on some Apple Mac computers.
If you do encounter a Firewire device and the motherboard does not provide Firewire ports, an
expansion card can be fitted.
A single bus can connect up to 63 devices. Like USB, the bus is powered and supports hot swapping.
The Firewire 400 standard used 6-pin “alpha” connectors and cabling.
The 6-pin connectors slightly resemble USB but have a beveled edge on one side.
There is also a 4-pin unpowered connector.
The maximum transfer rate is 400 Mbps.
The IEEE 1394b (Firewire 800) standard supported transfer rates up to 800 Mbps.
Firewire 800 used 9-pin (“beta”) connectors and cabling.
What are graphics devices?
While USB is used to connect a wide range of different peripheral devices, including keyboards, mice, scanners, cameras, and printers, it is not used to connect the computer display or graphics device.
The graphics interface can be provided by a number of different technologies.
A computer’s graphics system involves some sort of display unit, such as a flat-panel screen, connected to the computer via a video card (or graphics adapter). The video card generates the signals to send to the screen and provides support for one or more connection interfaces.
Low-end graphics adapters are likely to be included as part of the motherboard or CPU.
If a computer is to be used for 3D gaming or multimedia work, a better-quality expansion adapter is required.
This is often one of the key features distinguishing budget desktops and laptops from premium versions.
Most graphics adapters are based on chipsets by ATI/AMD (Radeon chipset), nVIDIA (GeForce and nForce chipsets), SiS, VIA, and Intel.
What is resolution and colour depth?
A computer image is made up of a number of pixels. The number of horizontal and vertical pixels gives the resolution of the image.
Each pixel can be a different color.
The total number of colors supported in the image is referred to as the color depth (or bit depth).
The other important component of video is the speed at which the display is refreshed, measured in Hertz (Hz).
Increasing any one of these factors increases the amount of bandwidth required for the video signal and the amount of processing that the CPU or GPU (Graphics Processing Unit) must do and the amount of system or graphics memory required.
IBM created VGA (Video Graphics Array) as a standard for the resolution and color depth of computer displays.
VGA specifies a resolution of 640x480 with
16 colors (4-bit color) at 60 Hz.
The VGA standard is long obsolete but was further developed by the Video Electronics Standards Association (VESA) as Super VGA (SVGA).
SVGA was originally 800x600 @ 4-bit or 8-bit color.
This was very quickly extended as the capabilities of graphics cards increased with the de facto XGA standard providing 1024x768 resolution, better color
depths (16- and 32-bit), and higher refresh rates.
Resolutions for modern display systems use some variant of the XGA “standard” (in fact, these are labels rather than standards).
Most computer displays now use a widescreen form factor (16:10) with a High Definition (HD) resolution such as 1280x720, 1360x768, 1600x900, or 1920x1080 (Full HD).
Larger display devices are likely to use even higher resolution, such as 3840x2160 (4K or Ultra HD).
What are graphic device interfaces?
There are many different types of graphic device/display connectors and cabling.
Many video adapters and display screens come with more than one type.
When computers were primarily used with Cathode Ray Tube (CRT) monitors, the graphics adapter would generate an analog video signal to drive the monitor. Now that most screens use flat-panel technology, the video signal is usually digital.
What is HDMI?
The High Definition Multimedia Interface (HDMI) is the most widely used graphic device interface.
It is ubiquitous on consumer electronics, such as
televisions and Blu-Ray players, as well as computer equipment.
HDMI supports both video and audio digital streams, plus remote control (CEC) and digital content protection (HDCP).
HDMI cabling is specified to different HDMI versions, the latest being 2.1.
Newer versions support higher bandwidths and consequently better resolutions (4K UHD for instance). HDMI uses a proprietary 19-pin (Type A) connector.
HDMI v1.3 introduced the Mini HDMI connector (Type C) for use on portable devices, such as camcorders. This is more compact but has the same number of pins.
HDMI v1.4 also introduces the even smaller Micro HDMI connector (Type D), still with 19 pins.
